Fittings and couplings for rigid conduit utilize a variety of mechanical relationships to sealingly interrelate the fitting and conduit. Bolts, flanges, threads, gaskets, ferrules, elastomeric seals and other components and relationships are commonly employed. Usually, fittings and couplings for conduit are relatively bulky in configuration and are of a diameter substantially greater than that of the conduit with which they are associated. Relatively complex and time consuming operations are usually required to assemble the fitting and conduit.
It is an object of the invention to provide a fitting for rigid threadless conduit utilizing a compressed elastomeric seal wherein a seal assembly is preliminarily associated and positioned within the fitting to facilitate and simplify fitting-conduit assembly.
Another object of the invention is to provide a fitting for rigid conduit utilizing an elastomeric seal wherein the seal is uniformly compressed to insure a fluid-tight relationship, and the fitting is economical to manufacture, concise in configuration, and readily mounted upon conduit with a minimum of skill.
An additional object of the invention is to provide a fitting for rigid threadless conduit wherein the fitting is tamper-proof and once assembled to a conduit, cannot be readily removed.
Another object of the invention is to provide a fitting for rigid conduit utilizing conduit positioning means within the fitting which accommodates limited conduit movement during the final stages of sealing.
Yet another object of the invention is to provide a coupling for connecting rigid conduit in end-to-end relationship employing a removable abutment for positioning the coupling to the conduit, but permitting the coupling to be installed on in-line conduit wherein axial conduit displacement is not permitted.
Yet an additional object of the invention is to provide a coupling for rigid conduit utilizing a conduit positioning abutment which may be selectively installed or removed exteriorly of the coupling to facilitate assembly of the coupling and conduit.
In the practice of the invention, the fitting includes a body defining a flow path intersecting a body end. A seal assembly is located within the flow path and includes an elastomer seal which is axially compressed by a compression ring. The conduit associated with the fitting is located within the seal assembly whereby compression of the elastomer seal deforms the elastomeric material radially inward into engagement with the conduit to produce a fluid-tight relationship.
The axial position of the compression ring is controlled by a spring steel retainer in the form of a band received within an annular groove within the compression ring. The band includes a plurality of cantilevered teeth having free ends, and several of the teeth substantially equally spaced about the circumference of the compression ring are deformed from the circular configuration of the band for selective engagement with a radially disposed abutment surface defined in the body adjacent the flow passage. The band is so oriented upon the compression ring, and certain teeth of the band are of such dimension, that these teeth cooperate with the body recess preventing withdrawal of the seal assembly from the body during a pre-assembly state of the seal assembly which locates the seal assembly components for reception of a conduit therein, but the elastomeric seal is not under compression.
When the conduit has been properly located within the seal assembly and body, the compression ring is axially displaced further into the body, compressing the elastomeric seal, and the retainer includes teeth of such dimension as to align with and engage the body recess shoulder to prevent axial withdrawal of the compression ring from the body once a full state of elastomeric seal compression has been achieved.
The compression ring retainer is simply formed of spring steel stock material and stamped to form a comb-like configuration wherein selected teeth may be deformed from the general plane of the band. The different lengths of the teeth permit the teeth to serve the functions of retaining the band within the compression ring groove, retaining the seal assembly within the body prior to compression of the seal and retaining the compression ring within the body during compression of the elastomeric seal.
The seal assembly may include a split ring internally serrated collar having a conical surface cooperating with an annular piston engaging the elastomeric seal having an oblique surface wherein the axial forces imposed upon the seal assembly by the compression ring cause the piston to inwardly deflect the split collar embedding the collar serrations into the conduit and thereby increasing the "grip" upon the conduit.
The compression ring is located within the confines of the body, and the construction of a fitting in accord with the invention produces a concise arrangement of components having a diameter only slightly greater than the diameter of the conduit with which the fitting is associated. Axial displacement of the compression ring may be produced by various means, and in the description below, and drawings, one type of hydraulically operated actuator is described.
The inventive concepts may be practiced within a coupling employed to align and maintain conduits in end-to-end relationship. In such a coupling, the body includes a flow passage extending therethrough and identical seal assemblies are located in the flow passage adjacent each coupling body end. Preferably, the central region of the body and flow path is internally provided with an abutment extending into the flow passage for engagement by the conduit end to limit insertion of the conduit into the body and properly orient the body and conduit prior to producing the sealed relationship.
As a coupling employing the invention may advantageously be employed in an existing conduit system to repair leaks, or permit the installation of a tee or other type fitting, it may be desirable to initially insert the coupling completely upon the conduit after laterally displacing aligned in-line conduits incapable of axial movement. In such instance the abutment would prevent such an excessive insertion of the conduit in the coupling, and, in accord with the invention, the abutment may be selectively removed to permit such installation.
When utilizing a seal assembly having a split collar having serrations, the compression of the split collar may impose slight axial movement upon the conduit during the final stages of seal assembly compression. Normally, the abutment within the coupling would resist such axial displacement of the conduit, but in accord with the practice of the invention the use of a wave spring as an abutment permits limited axial displacement during the final stages of sealing, and yet accurately axially aligns the coupling and conduit during initial assembly.